A majority of the 120 full-time and part-time drivers who transport those companies’ employees have signed authorization cards with the union, said Rome Aloise, International vice president and secretary-treasurer of Teamsters Local 853.

The drivers are employed by South San Francisco-based Compass Transportation, which has contracts with Apple and the other firms to transport its workers to and from work.

Although the hourly rates for the drivers range from $18-20, they argue that high living costs make it difficult to live close to work, and working further out does not allow them to return home between split shifts in the morning and evening–meaning they are effectively at work for far longer than their paid hours.

William Gould, a professor at Stanford Law School said: “These workers, as a practical matter, have to wait in certain areas to do their work (and) they are not compensated for that wait.”

Facebook shuttle bus drivers joined the Teamsters union in November. Although Google is not specifically named by the Teamsters, it’s believed that Google drivers will also be invited to vote on joining a union.

Google has faced criticism over its impact on the housing market in San Francisco as a result of well-paid employees being able to buy and rent property in the area, partly as a result of the wifi-equipped shuttle buses–with protestors blocking the buses. The company responded by donating $6.8M to a program offering free transit to low income kids, and funding four electric shuttle buses for use by the local community in Mountain View.